Method of making brick and other burned-clay products



Patented use 7, "lees.

start "r1 rerea .PGOLE MAYNARD, 0F ATLANTA, GEORGIA.

. METHOD OI! MAKING BRICK AND OTHER BUBNED-CLAY .PB/ODUGTS.

No Drewi n g.

yellow colored bricks may be manufactured to meet the demand.

The yellowish or bull color of burned clay wares is due to the iron oxide present in the clay and is obtained by burning the clay in an oxidizing atmosphere at a temperature above 2000 F. Thus a clay containing from one to two per cent of iron oxide may give a cream or buff color when burned in the ordinary manner. This color due to iron oxide may be markedly affected by other-substances present in the clay. Thus some clays carrying up to two percent in iron oxide with a high content of alumina may burn to yellow or bull colors, and other clays having a higheriron content as much as thqt and one-half per cent or even more, and ing a high percentage of alumina may but: to yellows and buffs. This apparent bleaching eflect of alumina upon the iron is not so marked or reliable-as that of lime. I

Clayscontaining approximately two and one-half to three and one-half per cent of iron oxide with lime present in about three times this quantity produce upon burning under the requi mditions, iron and lime compounds, which although possibly very complex in nature, give very reliable color eflects. I have found that mixtures of clays I and other materials when made tov approximate these quantities-oi iron and lime and burned in an oxidizing atmosphere above 2000 F. give very uniform, and reliable color effects in yellows and buffs,

This lime may be obtained from several difi'erent sources: Limestoneor its directly manufactured products maybe used, but seem to restrict the range of burning by w shortening the temperature limits between I incipient vitrification and viscosity. Lime feldspars could be used to advantage, but

.these deposits are widely scattered and I Wholly undeveloped.

I have found that the lime available in blast furnace slag, which is a cheap Waste product is particularly suitable for use in practicing the process. When blast furnace slag is employed it produces a good.- bleach,

I ide and lime.

Application and mm a, 1926. Serial 110.91%,355.

isrnot subject to rapid softening at higher temperatures and also has no loss upon 1gnition. l

The rangeof burning may be increased allowing better controlot the color develop ment in the kiln by the addition-of a .white refractory clay. This addition also aids in securing the proper proportions of iron ox- In practicing; the process an Qrdina clay having a high iron oxide content 15 mixed with a refractory clay having a very low iron oxide content and blast furnace slag to obtain a mixture havin a uniform. iron oxide content of substantia ythreeand the neighborhood of three per cent,.not over thirteen per cent of lime is employed.

' With the iron oxide content of the clay to be used in the neighborhood ofnine per cent, substantially thirty-live per cent of common clay is employed in the mixture,-' forty five per cent (if-refractory clay and twenty per cent of blast-furnace slag. it

the iron oxide content of the common clay varies the proportions are varied accordingly. A slight variation in proportion will not seriously affect the color or fusibility of I the product.

In preparing the mixture the slag may be ground" in a tube mill or like apparatus. The preparation of the refractory clay and the common clay will depend upon theground separately orfltog ether. The new tory clay may. be first calcined and then ground either in a. mixture withthecom mon clay andslag or individually. The clays maybe ground either separately or plant process.- They be dried and together in a wet pan. After the material has been mixed so as to'obtain a substantially uniform mixture the bricks are manufactured in the ordinary manner.

I am aware of the fact that molten slag has been cast into bricks and employed as a substitute for the ordinary clay brick, but such product is not the subject matter of the resent inyention and is specifically dis- While I have described in detail the preferred practice of my process, it is to be understood that the details of procedure and proportions of ingredients may be widely varied, and that known chemical equivalents maybe employed in place of thematerials mentioned, without departing from the spirit of the invention or the scope of.

' twenty-five per cent of-lime and burning at a temperature above 2000 F. to obtain an iron oxide content of from two and one-half to three and one-half per cent in the burned product. I

3. The process of making brick and other burned clay products which comprises forming a mixture of claysad'dingbla'st furnace slag in the proportion of less than twentyfive per cent and burning at a temperature of more than 2000 F. to obtain an iron oxide content of from two and one-half to three and one-half per cent in the burned product. I,

4:. The process of making brick'and other burned clay products which comprises forming a mixture 'of clays, adding blast turn ace slag in the proportion of substantially twenty per cent of the entire mixture and burning at a temperature above 2000 F. to obtain an iron oxide content of from two and one-half to three and one-half per cent in the burned product.

5. The process of making brick and other burned clay products which comprises adding' refractory clay to common clay, adding lime thereto in the proportion of less than twenty-five per cent, and burning ata tem perature of more than 200O F. to obtain a mixture having an iron content of from:

two and one-half to three and one-halt per' cent in the burned product.

ing refractory. clay to common clay, adding blast furnace slag thereto in the proportion 6. The process of making brickand-other burned clay pro'dnctswhich comprises add-i of substantially twenty per cent of the 61k tire mixture, and burning at a temperature above 2000 F. to obtain a mixture having an iron oxide content of from two and one half to three and one-half per cent in the burned product.

"7. The process of making brick and other hic burned clay products w comprises burning a mixture of clays having an iron oxide content of substantially three and one-half per cent with substantially ten per cent of lime at a temperature above 2000 F.

8. The process of making brick and other 'o ing a'mixture of clays, adding substantially;

burned clay products which comprises form- -ten per cent of lime, and burning at atemperature above 2000? F. to obtain an iron oxide content of substantially three and onehalf-per cent in the burned product.

burned clay products which comprises form- 'ing a mixture of clays, adding blast furnace 9. The process of making brick and other slag in the proportion of substantially tcn per cent, and burning at a temperature of above 2000 .F; to obtain an iron oxide content of substantially three and one-half per cent in the burned product.

10. The process of making brick and other burned clay products which comprises adding refractory clay to common clay, adding lime thereto in the proportionofsubstantially ten per cent, and burning at a tem- 

